Pneumatic rubber tires have various rubber components for which sometimes enhanced stiffness of the rubber composition is a desirable feature.
Enhanced stiffness of the rubber composition might be accomplished, for example, by an inclusion of a dispersion of a small content, or amount, of short fiber reinforcement.
Sometimes aramid short fibers in a form of a pulp are used to promote an increase of stiffness for a rubber composition, a practice which is well known by those having skill in such art.
For such practice, where the short fiber is a short aramid fiber pulp, natural cis 1,4-polyisoprene rubber is used to aid in dispersing the aramid short fiber pulp in a rubber composition.
For this invention, it is desired to evaluate an effect of substituting at least a portion of such natural cis 1,4-polyisoprene rubber with a functionalized sulfur curable elastomer such as, for example, an epoxidized natural rubber (epoxidized natural cis 1,4-polyisoprene rubber).
A challenge is therefore presented for enhancing short fiber reinforcement, particularly aramid short fiber pulp reinforcement of rubber compositions.
In the description of this invention, the terms “rubber” and “elastomer” where used, are used interchangeably, unless otherwise prescribed. The terms “rubber composition”, “compounded rubber” and “rubber compound”, where used, are used interchangeably to refer to “rubber which has been blended or mixed with various ingredients” and the term “compound” relates to a “rubber composition” unless otherwise indicated. Such terms are well known to those having skill in the rubber mixing and rubber compounding art.
In the description of this invention, the term “phr” refers to parts of a respective material per 100 parts by weight of rubber, or elastomer. The terms “cure” and “vulcanize” are used interchangeably unless otherwise indicated.